The invention relates to a stack of folded supple and absorbent sheets.
The invention relates more specifically to a stack of supple and absorbent sheets, particularly made of cellulose wadding, which has a longitudinal fold line forming a longitudinal border and at least one transverse fold line perpendicular to the longitudinal fold line.
These sheets may in particular be used as table napkins. They then consist of four supple panels separated from each other by a longitudinal fold line and a transverse fold line.
There are various types of stack.
The sheets may simply be placed one on top of the next, the longitudinal fold and the transverse fold of an upper sheet then being superposed with the respective longitudinal fold and transverse fold of a lower sheet.
The sheets may also be stacked in such a way that the transverse fold of the upper sheet is superposed with the edge opposite the transverse fold of the lower sheet, the longitudinal folds of the upper and lower sheets being superposed.
Another way of stacking the sheets consists in intertwining them.
In this case, having folded the sheets longitudinally, the sheets are folded transversely and are folded down alternately in one direction and in the opposite direction so that two sheets folded in the same direction are half inserted between the transverse fold of an intermediate third sheet folded in the opposite direction.
This last way of stacking makes it possible, when the upper sheet is pulled via its upper half, for this to pull the next sheet along also, by virtue of the forces of friction between the lower half of the upper sheet and the upper half of the intermediate lower sheet.
Such stacks of folded and intertwined sheets are used in particular for hand towels in areas of communal use. In general, the lower sheet of the stack is placed directly on a roughly horizontal flat surface, the stack extending vertically upwards.
Another common solution for table napkins consists in placing the stack of non-intertwined sheets inside a dispenser which consists of a body, the cross section of which roughly corresponds to the outline of the sheets. A pusher equipped with elastic means is located at one of the ends of the body and allows the lower sheet of the stack to be pushed longitudinally towards the other end which has an opening allowing the first sheet to be grasped. Such a dispenser is generally arranged so that its longitudinal axis is roughly horizontal.
To make storage easier and to reduce the amount of handling of the sheets, the stacks contain a high number of sheets. Now, such stacks are not symmetric with respect to their main axis of stacking and specifically are not geometrically symmetric because the thicknesses of the longitudinal and transverse folds of a sheet are greater than the thickness that corresponds to the superposition of the panels of the folded sheet, which leads to a lessening of the distribution of their mass with respect to the axis of stacking because the folded borders contain more material and are heavier than the free edges of the folded sheets.
The result of the dissymmetry of the stack is to unbalance the stack and, in some cases, to cause it to topple when it is placed vertically on a horizontal surface.
In addition, the sheet located at the top of the stack is not flat because the superposition of the folded borders causes its borders to be xe2x80x9craisedxe2x80x9d by comparison with the unfolded edges. This does not allow the longitudinal bulk of the stack to be minimized and may disrupt the operation of the supple sheet dispenser when such a dispenser is used.
The dissymmetry of the stack may also jam the dispenser in which it may be placed.
This is because when the upper sheet of the stack is pressed against the end of the dispenser which has the opening, the lower sheet is not perpendicular to the longitudinal axis, the thrusting forces applied by the elastic means then not being distributed uniformly over the lower sheet, which encourages malfunctioning and in particular encourages the pusher to jam or causes the lower sheets of the stack to become crumpled.
In order to remedy these drawbacks, the invention proposes a stack of supple sheets of the type described earlier, characterized in that the longitudinal and transverse fold lines of an upper sheet in the stack are not adjacent to the respective longitudinal and transverse fold lines of the previous lower sheet.
Thus, the stack has geometric symmetry and a distribution of the weight of the folded supple sheets which allow the stack to remain balanced with respect to the axis of stacking, regardless of the number of folded supple sheets.
According to other characteristics of the invention:
the longitudinal fold line of an upper folded sheet is parallel to and transversely opposite the longitudinal fold line of the previous lower folded sheet and the transverse fold line of the upper folded sheet is parallel to and longitudinally opposite the transverse fold line of the lower folded sheet;
two successive folded sheets are intertwined;
the longitudinal fold line of the upper folded sheet is superposed with the edge of the previous lower folded sheet which edge is the opposite edge to the longitudinal fold line of this lower folded sheet;
the longitudinal fold line of the upper folded sheet is transversely offset towards the outside of the stack with respect to the longitudinal edge of the previous lower folded sheet;
at least one of the transverse fold lines forming a transverse border of the upper folded sheet is superposed with the edge of the lower folded sheet which edge is the opposite edge to the corresponding transverse fold line that forms the transverse border of the lower folded sheet;
at least one of the transverse fold lines forming a transverse border of the upper folded sheet is longitudinally offset towards the outside of the stack with respect to the transverse edge of the previous lower folded sheet;
the longitudinal fold line delimits two sections, the transverse dimensions of which are roughly equal;
the longitudinal fold line delimits two sections, the transverse dimension of one of which is at most twice the transverse dimension of the other;
the sheets are folded about two transverse fold lines so as to form a central panel and two end flaps which extend facing one same side of the central panel;
the sheets are folded about two transverse fold lines so as to form a central panel and two end flaps, each of which extends facing one of the sides of the central panel;
each sheet is folded in four about a longitudinal fold line and about a perpendicular transverse fold line so as to form a stack of square folded sheets, particularly folded napkins;
each folded sheet of the stack consists of at least one ply of supple and absorbent material.
The invention also proposes a method for stacking sheets of supple and absorbent material, particularly cellulose wadding, of the type comprising the following successive steps:
folding two separate webs of material in the longitudinal direction about a longitudinal fold line;
making transverse cuts at regular intervals, so as to produce sheets;
folding the sheets about at least one transverse fold line; and
stacking the folded sheets,
characterized in that at the end of the stacking step, the longitudinal fold line of the upper folded sheet is roughly opposed, with respect to the lower folded sheet, to the longitudinal fold line of the lower folded sheet.
According to another characteristic of the method according to the invention, the folding and the stacking of the sheets cause the folded sheets to be intertwined.